[A clinicopathological study of malignant lymphoma in the orbital region and other sites]

I report a clinicopathological study of 226 cases of malignant lymphomas treated at Yamagata University Hospital during a period of 16 years. The most common site was the lymph nodes. The next most common sites were the pharynx-tonsils, gastro-intestinal tract, and skin. The median age of all patients was 55.0 years and the male-to-female ratio was 3:2. Histopathological study showed that 12 cases were Hodgkin's disease and 174 cases were non-Hodgkin's lymphoma, and in the latter group, diffuse large cell type was the most common. The cases that had a high grade of malignancy and were in an advanced clinical stage had a relatively poor prognosis. The patients with primary orbital malignant lymphoma were eight. Their median age was 69.8 years and the male-to-female ratio was 5:3. Histopathologically, there were 4 cases of small lymphocytic lymphoma and 4 of diffuse small cleaved cell lymphoma. Seven patients were in clinical stage I and one in stage IV. All of them had a favorable prognosis. The reasons for the favorable prognosis were, (1) orbital lymphoma was extranodal and metastasized lymph nodes were rare, (2) histopathological findings showed low or intermediate grade malignancy, and (3) orbital lymphoma can be found and treated at an early stage.